Sheet positioning device



C. F. SCHNEIDER SHEET POSITIONING DEVICE Filed Feb. 16, 1961 June 15, 1965 INVENTOR CHARLES F. SCHNEIDER ATTORNEY United States Patent 3,188,856 SHEET POSITIONING DEVICE Charles F. Schneider, Manor Township, Lancaster County, ,Pa., assignor to Armstrong Cork Company, Lancaster,

Pa., a corporation of Pennsylvania Filed Feb. 16, 1961, Ser. No. 89,820 2 Claims. (Cl. 7337.7)

This invention relates to a device for measuring and Controlling the movement of sheet material in a lateral direction. The device is of the type particularly adapted to be associated with automatic or semi-automatic machinery wherein it is desired to maintain a high degree of accuracy in positioning a moving, continuous strip or sheet of material with respect to the equipment operating thereon.

The need for a non-contact position-measuring device for guiding a moving, continuous sheet of material has long been recognized in the floor covering and related industries. Previous devices used for this purpose were of the contact type, photoelectric cell type, or an air jet of the type wherein a blast of air issuing from a small round orifice was used with appropriate controls to indicate or change the lateral position of a sheet. None of these were very satisfactory due to their inability to cope with a problem of vertical movement of the sheet to be guided and the need for continuous measurement and guidance rather than the on or off type of device.

This device differs from those currently in use in that the measurement and control of the lateral movement of a sheet is efiected continuously instead of periodically. Additionally, the vertical position of the sheet as it passes through the gap between the two components of the measuring device will not adversely affect the measurement and/ or control of the sheet as long as the vertical motion does not exceed 75% of the gap between the outlet nozzle and the receiver.

It is the general object of my invention to provide a simple, efiicient and relatively inexpensive sensing device which is automatic in operation and capable of continuously measuring and controlling the lateral movement of a sheet of material as it passes therethrough. Another object of this invention is to provide a control for a moving web which has no physical contact with the web proper. A further object of the invention is to provide a sensing device which will not be affected by the normal vertical movement of a sheet passing therethrough.

These objects are achieved by a device having an air discharge assembly and an air receiver assembly mounted in spaced opposing relationship. In measuring the lateral movement of a forwardly moving continuous sheet, the edge of the sheet is passed between the two assemblies. In normal operation, a constricted air stream of constant velocity passing from an elongated slot or opening in the tapered discharge nozzle to a beveled slot or opening in the receiver is partially blocked by the sheet edge as it passes between the two slots or openings. Lateral move ment of the sheet edge results in blocking off of more or less of the air stream. This variable blocking of the air stream causes variations in the static pressure in the receiver chamber. These pressure variations are measured and used to maintain correct positioning of the sheet by standard control means.

A more complete understanding of my invention will be attained from the following description taken in connection with the accompanying drawings, wherein like reference characters refer to similar parts throughout the several views and in which:

FIG. 1 is a side elevation of the sheet position sensing device of this invention with a sheet shown diagrammatically in its approximate position relative to the device as it would appear when the device is in operation;

Patented June 15, 1965 FIG. 2 is a front elevation of the device;

FIG. 3 is a sectional view of the device taken along the line IIIIII of FIG. 1;

FIG. 4 is a view looking down on the air discharge nozzle of FIG. 1; and

FIG. 5 is a view looking up into the air receiver portion of FIG. 1.

In the drawings there is shown a mounting bracket 1, having a cylindrical opening 2 adapted to be affixed to a supporting rod or the like (not shown) upon which bracket 1 is held by means of set screw 3. The air discharge nozzle 4 and the air receiver 5 are mounted in opposing relationship on supporting members 6 and 7, which in turn are mounted on bracket 1 and fastened thereto by means of slotted machine screws S. Cut-out portions 8 and 8a machined in bracket 1 receive members 6 and 7. Rectangular projections 9 and 10 and 9a andllia on cutout portions 8 and 8a respectively serve to position and hold members 6 and 7 and therefore discharge nozzle 4 and air receiver 5 in proper vertical alignment with each other. Supporting members 6 and 7 are drilled to provide air ducts 11 and 12 for the movement of air from air chamber 13 to air chamber 14 and then through duct 12 to a standard pneumatic measuring device R. Discharge nozzle 4 mounted directly above chamber 13 has portions of its sides beveled as at 1 5 at an included anglewhichmay be 15, and has an elongated slot or opening 16 therein (see FIG. 4) which may be .007" wide, /8" long, and 1" deep, for the discharge of air to the receiver 5. In the receiver 5 is an elongated air receiving slot or opening 17 (see FIG. 5) whose sides are beveled at an angle of 30 as indicated at 18 and best seen in FIG. 3. Slot 17 may be 5 8" long and preferably .010" wider than the slot 16 in air discharge nozzle 4. Air entering the slot 17 is received in chamber 14, and by means of duct 12 and connecting means C is measured for pressure variations by standard pneumatic relay means R.

In operation of the device, air at a constant pressure is supplied to chamber 13 through duct 11 for discharge through air jet nozzle 4. Operating air pressure in chamber 13 may be within the range of from 1 to 2 pounds per square inch gauge. A 2 pounds per square inch gauge pressure in said chamber would result in an air velocity through slot 16 of about 2,000 feet per minute. With no sheet edge obstructing the flow of air from the nozzle 4 into the receiver chamber 14, an air velocity of this magnitude would result in a pressure in the receiver chamber 14 equal to a /2" column of water of 4 of a pound. The tapered external configuration of nozzle 4 contributes greatly to the constricted nature of the high velocity air stream issuing from elongated slot 16 by providing a smooth, streamlined surface for the flow of induced air. The air jet is directed into the oppositely positioned receiver 5 and is partially blocked in its passage by the projection of the sheet edge thereinto, The slot 17 in the receiver 5 being beveled facilitates entrance of the air stream into the receiver chamber 14, increasing the positive pressure therein. This pressure will be proportional to and will vary with the lateral location of the edge of the sheet as it moves through the gap between the air discharge nozzle 4 and the receiver 5. The changing static pressure in the receiver chamber 14 is connected to a standard pneumatic amplifying relay R such as that manufactured by the Moore Products Company of Philadelphia. This signal in turn may be used for the measure ment and/ or control of guiding systems and other devices where an input is desired that may be used to maintain the desired sheet position.

I claim:

1. A non-contact apparatus for controlling lateral movement of a forwardly moving, vertically fluctuating, continuous sheet comprising an air discharge assembly and an air receiving'assembly mounted .in spaced opposing relationship to allow continuous vertically variable translatory movement of a sheet therebetween with a substan 'tial reductionin receiver pressure variations'due to said vertical movement, said air discharge-assembly comprising an air chamber adapted to be connected to a source of air under constant pressure, a nozzle mounted'on said air 7 discharge assembly having beveled outer surfaces on the longitudinal sides thereof and a narrow elongated slot therein for discharging a constricted high velocity stream air stream, a beveledsubstantially rectangular opening in 7 said oppositely mounted air receiver assembly, said opening being widened at its outer portion and having at least two sides inclined-inwardly from said outer portion and terminating in an elongated slot of slightly greater dimensions than the slot in the discharge nozzle, said en-.

10 of air past the edge of a sheet partially intercepting said forwardly moving continuous sheet of material which ceiver havinganinwardly' beveled opening therein terminatin'g in an elongated air receiving slot of slightly greater larged outer portion and inwardly inclined sides of said receiver opening all adapted to receive and'channel said high velocity air stream from said oppositely mounted discharge nozzle into the receiver chamber with a minimum of turbulence to obtain maximum measurable pres sures therein, said pressures being substantially unaifected by vertical movement of the sheet edge ina range of from 075% of the space between the air discharge and air 7 receiving members.

2. A non-contact position sensing device for continuously measuring and controlling lateral movement of a dimensionstthan said discharge slot and oppositely positioned thereto'in the path of said air stream and a suflicient distance away from said air discharge opening to allow translatory and vertical movement of the edge of a sheet therebetween partially intercepting said air stream.

References Cited by the Examiner UNITED 'STATESH PATENTS 2,244,864 6/41 Witham 73-377 2,794,444 6/57 Markey j 73' 37.7

FOREIGN PATENTS 442,365 2/36' Great Britain.

ISAAC LISANN', Primary Examiner. 

1. A NON-CONTACT APPARATUS FOR CONTROLLING LATERAL MOVEMENT OF A FORWARDLY MOVING, VERTICALLY FLUCTUATING, CONTINUOUS SHEET COMPRISING AN AIR DISCHARGE ASSEMBLY AND AN AIR RECEIVING ASSEMBLY MOUNTED IN SPACED OPPOSIING RELATIONSHIP TO ALLOW CONTINUOUS VERTICALLY VARIABLE TRANSLATORY MOVEMENT OF A SHEET THEREBETWEEN WITH A SUBSTANTIAL REDUCTION IN RECEIVER PRESSURE VARIATIONS DUE TO SAID VERTICAL MOVEMENT SAID AIR DISCHARGE ASSEMBLY COMPRISING AN AIR CHAMBER ADAPTED TO BE CONNECTED TO A SOURCE OF AIR UNDER CONSTANT PRESSURE, A NOZZLE MOUNTED ON SAID AIR DISCHARGE ASSEMBLY HAVING BEVELED OUTER SURFACES ON THE LONGITUDINAL SIDES THEREOF AND A NARROW ELONGATED SLOT THEREIN FOR DISCHARGING A CONSTRICTED HIGH VELOCITY STREAM OF AIR PAST THE EDGE OF SHEET PARTIALLY INTERCEPTING SAID AIR STREAM, A BELVELED SUBSTANTIALLY RECTANGULAR OPENING IN SAID OPPOSITELY MOUNTED AIR RECEIVER ASSEMBLY, SAID OPENING BEING WIDENED AT ITS OUTER PORTION AND HAVING AT LEAST TWO SIDES INCLINED INWARDLY FROM SAID OUTER PORTION AND TERMINATING IN AN ELONGATED SLOT OF SLIGHTLY GREATER DIMENSIONS THAN THE SLOT IN THE DISCHARGE NOZZLE, SAID EN- 